|
St Griede Licence, onshore Aquitaine Basin (50%)
Issued: April, 2008
Area: 1,238 sq/kilometres
Holder: Gas to Grid ("G2G")- 50%; Flow Energy Ltd- 50%
Term: 5 years
Commitment: Year 1 (2009): Euro 635,500 (G&G Studies)
Year 2 (2010): Euro 306,900 (Airborne Gravity Survey)
Year 3 (2011): Euro 1,548,900 (400 kms seismic)
Year 4 and Year 5 (2012-2013): Euro 1,860,000 (2,500 m well)
Background
The St. Griede licence was awarded by the French Government to Gas2Grid Limited ("GGX" - 50%) and its joint venture partner Gippsland Offshore Petroleum Limited ("GOP" - 50%) on the 21st April, 2008 after a two year application process. The licence covers 1,238 square kilometres within the onshore part of the Aquitaine Basin, north and east of the city of Pau in the south of France.
The licence has been awarded for a 5 year term with an aggregate total work commitment of pproximately AU$3.7 million. The licence is already covered by a regional grid of seismic data and there are a number of petroleum exploration wells that have been drilled both within and surrounding the licence. Three oil fields are located a few kilometres west of the licence boundary. Existing technical data is being acquired from the French Government and initial activities will include integration of existing petroleum well information, seismic reprocessing and the acquisition of airborne gravity.
Company representatives have met with French Government officials and the Company is in the process of purchasing relevant archived seismic field data for re-processing and also available data from previously drilled wells. The French Government reains processed sesimic data confidential forever and purchase of these data needs to be negotiated with the company the title holder at the time of acquisition and it only makes seismic field data available after 10 years of acquisition. All seismic data recorded within the St. Griede licence is older than 10 years and therefore that field data is available for purchase.
The Aquitaine Basin is a prolific hydrocarbon province with a long history of discovery and production. Over 13,000 petajoules (approximately 13 trillion cubic feet) of gas and 450 million barrels of liquid hydrocarbons have been discovered within the basin, mainly by the large French Government owned corporations. There has been a hiatus in exploration activity since the 1980s but a resurgence of licensing activity and operations has occurred recently, coincident with the increase in both oil and natural gas prices. There has been no seismic acquisition nor any drilling activity within the area covered by the St. Griede licence for more over 10 years and in fact until very recently, when three wells were drilled, there had been no drilling activity within the whole Aquitaine Basin for more than 10 years.
Geology
The Aquitaine basin is a depression located in front of Pyrenees Mountains, to the south of the Massif Central, the basin merges to the east with basins of the Provence regionand to the west, the basin is continuous with the Bay of Biscay. The Aquitaine basin developed since the Triassic on a heterogeneous Paleozoic basement, which is generally interpreted as a segment of the southern branch of the Variscan orogeny of Paleozoic age. Late Carboniferous and Permian troughs up to a few thousand meters thick have developed locally as a result of post-Variscan stress releases.
In Mesozoic times, a major hinge line (the "Celtaquitaine flexure") running from Arcachon in the NW, to Toulouse in the SE, separated a stable and relatively less subsiding platform to the northeast from more rapidly subsiding basins and intervening highs to the southwest. The latter area can be subdivided into two distinct domains:
In the south, the northern edge of the Pyrenees thrust belt and its moderately folded foreland developed as a foreland basin from late Cretaceous to late Eocene. This area is generally termed the Ardour Basin and contains the Arzacq, Tarbes and Commings sub-basins;
To the west, the Parentis basin which has been interpreted as a rapidly subsiding trough related to the opening of the Bay of Biscay in late Jurassic and early Cretaceous times. Total Mesozoic sediment thickness is in the order of 5 km.
To the north-east is the Mirande sub-basin, which has see relatively little drilling and exploration. Triassic salt features are recognisable
The Mesozoic stratigraphy of the thrust belt and the foreland deep basins is shown in the stratigraphy of the Arzacq Basin. Total sedimentary thickness is up to 12 km and hydrocarbons occur in clastic and carbonate sequences from Jurassic to Eocene age.
The Parentis Basin is characterised by a more condensed sequence, but nevertheless it has a total sedimentary thickness in its western, onshore portion of about 6- 7 kilometres. Hydrocarbons occur in late Jurassic and Cretaceous carbonates including bioherms and also as Cretaceous clastics.
Petroleum History: The western half of the French Pyrenees and their immediate foreland is the most prolific gas-bearing province in France. The two major gas fields, Lacq (deep pool) and Meillon produce from deep and structurally complex traps. The producing intervals are late Jurassic and Neocomian dolostones and the petroleum source-rocks are Kimmeridgian marl and limestone. Porosities are generally low, but dolomitisation and highly fractured zones greatly enhance reservoir productivity. In the same area, six other fields are also currently producing from the same stratigraphic intervals and also from younger (Senonian) or older levels (Liassic).
The Aquitaine basin has a number of distinctive sub-basins which have been explored with varying degrees of intensity and which are, from north east to southwest as follows:
The Ardour Basin in SW France is the principal area of French oil and gas production and hence will likely be an interesting place to explore for further hydrocarbon accumulations. A long history of structural deformation and sedimentary deposition has resulted in prolific oil and gas generation in the basin. The St. Griede licence is located beside the Pecorade, Vic-Bilh, Castera-Lou, Lagrave, and Lameac oil fields.
The southern part of the St. Griede licence is located in the northern part of the Tarbes Basin which has been a focus of oil generation and migration from the late Albian (early Cretaceous) into the Tertiary. No significant exploration has been undertaken in this area for the last 20 years and the early focus of the exploration effort will entail acquisition of an aero-magnetic survey and seismic reprocessing and reinterpretation to investigate subtle traps along the flank of the Tarbes Basin.
There are 2 principal trap types- compressional anticlines modified by salt movement and unconformity traps on the flanks of salt structures. The structures in the Ardour Basins have been deformed by extensional block faulting followed by Pyrenean compression with most structures influenced by salt tectonism. The basin morphology has been produced by the combined effects of the complex extension-compression-salt intrusion tectonic history of the Pyrenean region.
The northern part of the St. Greide licence is located in the Mirande Basin immediately to the northeast of the Audignon salt ridge, north of the Pecorade oil field, and the composite Garlin- Maubourguet- Antin salt ridge, north of the Lagrave, Castera-Lou and Lameac oil fields. The break between the salt ridges will have likely acted as a hydrocarbon migration pathway from the prolific southern basins into the Mirande Basin. This area has seen almost no exploration activity in the last 20 years - only 3 wells have been drilled in the last 19 years. Seismic data coverage in some areas is sparse and future work will include the acquisition of additional seismic data in order to define prospects for drilling in the later years of the license.
The complex structural history of the area has resulted in the development of many highly prospective structural traps. The compressional events at the end of the Jurassic (Neocomian), the end of the Aptian and Albian and in the Late Cretaceous-Tertiary have produced structures structural traps attractive to exploration.
Reservoirs
The main reservoir sections are Jurassic dolomites and Barremian limestones, and their distribution is defined by the Jurassic and early Cretaceous palaeogeography. The stratigraphic chart highlights the main reservoir targets which are located in the Jurassic and Eraly Cretaceous.
Markets and infrastructure are well developed and the commercialisation of even small discoveries is not expected to be problematic.
|
|